Hobøl is a municipality in Østfold county, Norway. The administrative centre of the municipality is the village of Elvestad. Hobøl is situated about southeast of Oslo. The parish of Haabøl was established as a municipality on 1 January 1838 (see formannskapsdistrikt).
The largest village in Hobøl is Tomter, whose railway station is served by Indre Østfoldbanen. Other villages in the municipality are Knapstad, Ringvoll, and the middle part of the municipality which is called Hobøl.
Hobøl was suggested as the replacement site for a new airport to replace Fornebu, and in 1972 the Norwegian parliament voted to build it there. The 1973 oil crisis postponed that plan, and the new airport was finally built at Gardermoen, north of Oslo.